Method and apparatus for managing interference in a communication device

ABSTRACT

A system that incorporates teachings of the present disclosure may include, for example, a matching network including a tunable reactance circuit configured to be coupled to at least one of a transmitter portion and a receiver portion of a communication device, where the tunable reactance circuit is adjustable to a plurality of tuning states, and where the determination of a tuning state is based on whether detected signal measurements are determined to be invalid and is based on information from at least one of an open-loop or closed-loop feedback configuration of the tunable reactance circuit. Additional embodiments are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/090,575, filed Apr. 20, 2011, which claimspriority to U.S. Provisional Application Ser. No. 61/326,206 filed onApr. 20, 2010, the disclosures of which are hereby incorporated byreference in their entirety. This Application is also related to U.S.application Ser. No. 13/090,583 entitled “Method and Apparatus forManaging Interference in a Communication Device” filed Apr. 20, 2011,the disclosure of which is hereby incorporated by reference in itsentirety.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to communication deviceoperations, and more specifically to a method and apparatus for managinginterference in a communication device.

BACKGROUND

The quality of wireless communications between wireless access pointssuch as Wireless Fidelity (WiFi) or cellular base stations and portablemobile devices such as cell phones and laptop computers can depend onmany factors. For example, an antenna's performance in a portable devicecan be impacted by its operating environment. Multiple use cases canexist for radio handsets, which include such conditions as the placementof the handset's antenna next to a user's head, or in the user's pocketor the covering of an antenna with a hand, which can significantlyimpair wireless device efficiency. Similarly, the quality of wirelesscommunications can be affected by network topology and location of themobile device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an illustrative embodiment of a communication device;

FIG. 2 depicts an illustrative embodiment of a portion of a transceiverof the communication device of FIG. 1;

FIGS. 3-4 depict illustrative embodiments of a tunable matching networkof the transceiver of FIG. 2;

FIGS. 5-6 depict illustrative embodiments of a tunable reactive elementof the tunable matching network;

FIGS. 7-8 depict illustrative embodiments of portions of communicationdevices with tunable matching networks;

FIG. 9 depicts a method operating in portions of the communicationdevice of FIGS. 7-8;

FIG. 10 depicts an illustrative embodiment of a portion of communicationdevices including a power and phase detector;

FIG. 11 depicts an illustrative embodiment of a frequency diagram forthe communication device of FIG. 10;

FIGS. 12-16 depict illustrative embodiments of portions of communicationdevices including power and phase detectors;

FIGS. 17-18 depict illustrative embodiments of exemplary timingdiagrams;

FIG. 19 depicts an illustrative embodiment of a portion of acommunication device including a power and phase detector;

FIG. 20 depicts an exemplary diagrammatic representation of a machine inthe form of a computer system within which a set of instructions, whenexecuted, may cause the machine to perform any one or more of themethodologies disclosed herein.

DETAILED DESCRIPTION

One embodiment of the present disclosure entails a computer-readablestorage medium comprising computer instructions to detect an existenceof an interferer and determine a tuning state of a matching networkhaving a tunable reactance, where the determination of the tuning stateis based on whether the interferer exists and is based on informationfrom at least one of an open-loop or closed-loop feedback configuration.

One embodiment of the present disclosure entails a matching network,comprising: a tunable reactance circuit configured to be coupled to atleast one of a transmitter portion and a receiver portion of acommunication device, wherein the tunable reactance circuit isadjustable to a plurality of tuning states, and wherein thedetermination of a tuning state is based on whether an interferer existsand is based on information from at least one of an open-loop orclosed-loop feedback configuration of the tunable reactance circuit.

One embodiment of the present disclosure entails a method comprisingdetecting interference with a communication device based on an existenceof an interferer and determining a tuning state of a variable matchingnetwork of the communication device based on whether the interfererexists.

One embodiment of the present disclosure entails a communication devicecomprising a controller to determine a tuning state of a variablematching network that controls one or more operational characteristicsof at least one of a receiver portion and a transmitter portion of thecommunication device, where the controller is operable to detect anexistence of an interferer and determine the tuning state based onwhether the interferer exists and based on information from at least oneof an open-loop or closed-loop feedback configuration.

One embodiment of the present disclosure entails a method comprisingdetecting an existence of an interferer that is interfering with acommunication device; determining a tuning state of a variable matchingnetwork of the communication device based on whether the interfererexists; and adjusting the variable matching network based on thedetermined tuning state only when the existence of the interferer is notdetected.

One embodiment of the present disclosure entails a method comprisingdetecting interference with a communication device sourced by aninterferer; and determining a tuning state of a variable matchingnetwork of the communication device based on the detected interference.

One embodiment of the present disclosure entails a method comprisingdetermining parameters of interference with a communication device, theinterference being sourced by an interferer; and adjusting a tuningstate of a variable matching network of the communication device basedon the interference parameters.

One embodiment of the present disclosure entails a matching networkcomprising a tunable reactance circuit configured to be coupled to atleast one of a transmitter portion and a receiver portion of acommunication device, wherein the tunable reactance circuit isadjustable to a plurality of tuning states, and wherein thedetermination of a tuning state is based on parameters associated with adetected interference.

One embodiment of the present disclosure entails a non-transitorycomputer-readable storage medium comprising computer instructions todetermine interference with a communication device; and adjust a tuningstate of a variable matching network of the communication device basedon parameters associated with the interference.

FIG. 1 depicts an exemplary embodiment of a communication device 100.The communication device 100 can comprise a wireless transceiver 102(herein having independent transmit and receiver sections, a userinterface (UI) 104, a power supply 114, and a controller 106 formanaging operations thereof. The wireless transceiver 102 can utilizeshort-range or long-range wireless access technologies such asBluetooth, WiFi, Digital Enhanced Cordless Telecommunications (DECT), orcellular communication technologies, just to mention a few. Cellulartechnologies can include, for example, CDMA-1X, WCDMA, UMTS/HSDPA,GSM/GPRS, TDMA/EDGE, EV/DO, WiMAX, and next generation cellular wirelesscommunication technologies as they arise.

The UI 104 can include a depressible or touch-sensitive keypad 108 witha navigation mechanism such as a roller ball, joystick, mouse, ornavigation disk for manipulating operations of the communication device100. The keypad 108 can be an integral part of a housing assembly of thecommunication device 100 or an independent device operably coupledthereto by a tethered wireline interface (such as a flex cable) or awireless interface supporting for example Bluetooth. The keypad 108 canrepresent a numeric dialing keypad commonly used by phones, and/or aQwerty keypad with alphanumeric keys. The UI 104 can further include adisplay 110 such as monochrome or color LCD (Liquid Crystal Display),OLED (Organic Light Emitting Diode) or other suitable display technologyfor conveying images to an end user of the communication device 100. Inan embodiment where the display 110 is a touch-sensitive display, aportion or all of the keypad 108 can be presented by way of the display.

The power supply 114 can utilize common power management technologies(such as replaceable batteries, supply regulation technologies, andcharging system technologies) for supplying energy to the components ofthe communication device 100 to facilitate portable applications. Thecontroller 106 can utilize computing technologies such as amicroprocessor and/or digital signal processor (DSP) with associatedstorage memory such a Flash, ROM, RAM, SRAM, DRAM or other liketechnologies.

FIG. 2 depicts an illustrative embodiment of a portion of the wirelesstransceiver 102 of the communication device 100 of FIG. 1. In GSMapplications, the transmit and receive portions of the transceiver 102can include common amplifiers 201, 203 coupled to a tunable matchingnetwork 202 and an impedance load 206 by way of a switch 204. The load206 in the present illustration can be an antenna as shown in FIG. 1(herein antenna 206). A transmit signal in the form of a radio frequency(RF) signal (TX) can be directed to the amplifier 201 which amplifiesthe signal and directs the amplified signal to the antenna 206 by way ofthe tunable matching network 202 when switch 204 is enabled for atransmission session. The receive portion of the transceiver 102 canutilize a pre-amplifier 203 which amplifies signals received from theantenna 206 by way of the tunable matching network 202 when switch 204is enabled for a receive session. Other configurations of FIG. 2 arepossible for other types of cellular access technologies such as CDMA.These undisclosed configurations are contemplated by the presentdisclosure.

FIGS. 3-4 depict illustrative embodiments of the tunable matchingnetwork 202 of the transceiver 102 of FIG. 2. In one embodiment, thetunable matching network 202 can comprise a control circuit 302 and atunable reactive element 310. The control circuit 302 can comprise aDC-to-DC converter 304, one or more digital to analog converters (DACs)306 and one or more corresponding buffers 308 to amplify the voltagegenerated by each DAC. The amplified signal can be fed to one or moretunable reactive components 504, 506 and 508 such as shown in FIG. 5,which depicts a possible circuit configuration for the tunable reactiveelement 310. In this illustration, the tunable reactive element 310includes three tunable capacitors 504-508 and an inductor 502 with afixed inductance. Other circuit configurations are possible, and therebycontemplated by the present disclosure.

The tunable capacitors 504-508 can each utilize technology that enablestunability of the capacitance of said component. One embodiment of thetunable capacitors 504-508 can utilize voltage or current tunabledielectric materials such as a composition of barium strontium titanate(BST). An illustration of a BST composition is the Parascan® TunableCapacitor. In another embodiment, the tunable reactive element 310 canutilize semiconductor varactors. Other present or next generationmethods or material compositions that can support a means for a voltageor current tunable reactive element are contemplated by the presentdisclosure.

The DC-to-DC converter 304 can receive a power signal such as 3 Voltsfrom the power supply 114 of the communication device 100 in FIG. 1. TheDC-to-DC converter 304 can use common technology to amplify this powersignal to a higher range (e.g., 30 Volts) such as shown. The controller106 can supply digital signals to each of the DACs 306 by way of acontrol bus of “n” or more wires to individually control the capacitanceof tunable capacitors 504-508, thereby varying the collective reactanceof the tunable matching network 202. The control bus can be implementedwith a two-wire common serial communications technology such as a SerialPeripheral Interface (SPI) bus. With an SPI bus, the controller 106 cansubmit serialized digital signals to configure each DAC in FIG. 3 or theswitches of the tunable reactive element 404 of FIG. 4. The controlcircuit 302 of FIG. 3 can utilize common digital logic to implement theSPI bus and to direct digital signals supplied by the controller 106 tothe DACs.

In another embodiment, the tunable matching network 202 can comprise acontrol circuit 402 in the form of a decoder and a tunable reactiveelement 404 comprising switchable reactive elements such as shown inFIG. 6. In this embodiment, the controller 106 can supply the controlcircuit 402 signals via the SPI bus which can be decoded with commonBoolean or state machine logic to individually enable or disable theswitching elements 602. The switching elements 602 can be implementedwith semiconductor switches or micro-machined switches such as utilizedin micro-electromechanical systems (MEMS). By independently enabling anddisabling the reactive elements (capacitor or inductor) of FIG. 6 withthe switching elements 602, the collective reactance of the tunablereactive element 404 can be varied.

The tunability of the tunable matching networks 202, 204 provides thecontroller 106 a means to optimize performance parameters of thetransceiver 102 such as, for example, but not limited to, transmitterpower, transmitter efficiency, receiver sensitivity, power consumptionof the communication device, a specific absorption rate (SAR) of energyby a human body, frequency band performance parameters, and so on.

To achieve one or more desirable performance characteristics which adesigner can define, the communication device 100 can be placed in ananechoic chamber. In this configuration, the designer can performcalibration measurements of performance parameters of the communicationdevice 100 such as Total Radiated Power (TRP), Total IsotropicSensitivity (TIS) or Radiated Harmonics measurements, receiverefficiency, transmit power efficiency, and power consumption, just tomention a few. For a multi-frequency band communication device 100, thecalibration measurements can be performed per band or per sub-band.

Additionally, the calibration measurements can be performed under anumber of use cases of the communication device 100 utilizing a phantombody that emulates the composition of a human body. For instance, acommunication device 100 having a housing assembly of a flip design, thecommunication device 100 can be placed next to an ear of the phantomwhen the flip is open to emulate a typical conversational use case. In ahands-free application such when a user utilizes a Bluetooth headset orwhen the communication device 100 is in standby mode, the communicationdevice 100 can be placed on a hip of the phantom with the flip closed.Calibration can be performed on other use cases such as antenna up, ordown, speakerphone feature “ON” with communication device 100 held witha phantom hand but away from the phantom head. Any number of use casescan be applied to each frequency band and sub-band if desirable.

FIG. 7 depicts an exemplary embodiment of a portion of a communicationdevice 700 (such as device 100 in FIG. 1) having a tunable matchingnetwork which can include a number of components such as a directionalcoupler 710, a detector(s) 720, a High Voltage Application SpecificIntegrated Circuit (HVASIC) 730 and a tuner 740 (such as an AdaptiveImpedance Matching Module (AIMM) tuner)). The tunable matching networkcan include various other components in addition to or in place of thecomponents shown, including components described above with respect toFIGS. 1-6. The tunable matching network can be coupled to an antenna 780and a transceiver (or transmitter and/or receiver) for facilitatingcommunication of signals between the communication device and anotherdevice or system. In this exemplary embodiment, the communication device700 is in proximity to an interferer 790 which is interfering with thetransmission and reception of signals by the device. Various RF levelsare depicted which include a desired range for the transmission level of0 to +33 dBm. The present disclosure contemplates other RF levels beingutilized or encountered. As can be seen, the introduction of theinterferer 790 can result in undesired tuning of the device 700.

FIG. 8 depicts an exemplary embodiment of a portion of a communicationdevice 800 (such as device 100 in FIG. 1) having a tunable matchingnetwork which can include a number of components such as a coupler 810,a detector(s) 820, a High Voltage Application Specific IntegratedCircuit (HVASIC) 830 and a tuner 840 (such as an Adaptive ImpedanceMatching Module (AIMM) tuner)). The tunable matching network can includevarious other components in addition to or in place of the componentsshown, including components described above with respect to FIGS. 1-6.The tunable matching network can be coupled to an antenna 880 and atransceiver (or transmitter and/or receiver) for facilitatingcommunication of signals between the communication device and anotherdevice or system. In this exemplary embodiment, the communication device800 is in proximity to an interferer 890 which is disrupting the tunercontrol loop, such as the measurement of the antenna VSWR by the device.

Device 800 can include one or more components that allow for thedetection of the interferer and an adjustment to the tuning techniquebased on the interferer detection. For instance, in one exemplaryembodiment, the AIMM algorithm can act as a look-up table of tuningstates but subject to updating the tuning state when valid measurementscan be made. When a measurement is determined to be invalid, then thedevice can utilize the last known valid tuning state for the particularuse case. Other adjustments to the tuning technique can also beutilized. For instance, the tuning can be delayed, such as for apredetermined period of time, until a valid measurement can be made. Inanother embodiment, if a valid measurement cannot be made within thepredetermined time period then the last known valid tuning state for theparticular use case can be utilized for tuning.

In one embodiment, isolation between antennas inside the device 800 canbe maintained in order to reduce the power of internally generatedinterferers (such as WiFi and Bluetooth) that are detected at thecoupler outputs. The particular level of isolation that is utilized canvary. Examples of multiple antenna systems in communication devices,such as diversity antenna systems, are described in U.S. patentapplication Ser. No. 13/005,122 filed on Jan. 12, 2011, the disclosureof which is hereby incorporated by reference in its entirety.

In another embodiment, one or more filters 850 can be coupled to thecoupler 810. The particular type of filter can vary and can includeBT/WiFi elimination filters or BP filters. For example, these filterscan be band rejection or band “suckout” circuits. The filter can be asingle filter coupled to the reflection output of the coupler 810, butthe present disclosure contemplates filters coupled to both outputs ofthe coupler. In one embodiment, 2.4 GHz elimination filters can becoupled to the output ports of the directional coupler, although otherfilter ranges can also be utilized.

In one embodiment, a filter 860 (such as a BP filter) can beincorporated into the coupler 810. For instance, since couplers can bebuilt in a multi-layer dielectric structure, filter elements can beincorporated into the structure to deploy the types of band reject orelimination filters desired.

While the previous embodiments have described the use of a directionalcoupler to detect the VSWR or impedance of the tunable matching networkas the source of feedback for the algorithm controlling the tunablenetwork, there are other possible components, techniques and/or means todetermine the impedance of the network, or to supply inputs to analgorithm designed to tune the tunable matching network. Known methodsfor determining impedance matching can also be utilized with theexemplary embodiments described herein. It should be noted that thetechniques to avoid and mitigate interfering signals described hereincan be applied to other means of determining feedback for the controlalgorithm.

In another embodiment, a peak detector 870 and an average detector 875can be coupled to or included within the sensor IC 820 to determine thepresence of amplitude modulation such as through comparing forward toreverse output data on constant envelope signals. In one embodiment, thepeak and average measurements on the difference between the forward andreverse signals can ignore the transmitter's intentional modulation butdetect amplitude modulation from the beat note which is generated by thecombination of the desired and interfering signals being presentsimultaneously.

The exemplary embodiments described herein allow a communication deviceto mitigate the effects of an interferer that is generating interferencethat is affecting the communication device. In one embodiment, thedevice can implement a multi-thread antenna tuning algorithm. Forinstance, an open loop look-up table can operate to store the nominaltuning state for each band, sub-band, mechanical position, speakerstate, etc. (use cases). When transmitting, the algorithm can run todetermine if a better tuning state can be found, and can continuouslyimprove it. The tuning state in the look up table can be replaced as thealgorithm finds better tuning states for the particular use case inoperation. Each Return Loss (RL) or impedance measurement can be checkedfor validity before the algorithm is allowed to update the tuning state.If an RL measurement is deemed invalid (such as for a single iteration)then the tuner state may not be changed.

Method 900 can begin with step 902 in which an RF signal is analyzed inorder to perform impedance matching using one or more of the componentsand/or systems described above, including the AIMM tuner 840. In oneembodiment, the AIMM algorithm can act as a look-up table of tuningstates, which can be updated based on measurements that are determinedto be valid. Method 900 can be based on closed-loop and/or open-loopfeedback. For instance, the RF signal can be analyzed using closed-loopfeedback in combination with open-loop feedback, such as based on storedinformation that is correlated to a physical state of the device (e.g.,in a flipped-open position). The present disclosure also contemplatesperforming one or more of the steps of method 900 based on onlyopen-loop feedback or based on only closed loop feedback. In step 904,the tuning state can be determined based on the analysis and thefeedback described above.

Measurements can then be validated in step 906, such as to detect theexistence of an interferer. Validation can be performed in a number ofdifferent ways. In one embodiment, a number of return loss phasemeasurements can be taken over time. A comparison of the maximum tominimum values can be done, and validity can be based on the range beingless than a predetermined threshold. For instance, if an interferingsignal is present for only some of the measurements, an assumption canbe made that the phase of the interfering signal will be different fromthat of the transmission forward and reflected signals. The timing ofthe measurements can be long enough such that one burst of a WiFi orother interfering transmission would not be present in all of themeasurements, and at least one measurement would fall in betweentransmission bursts. In another embodiment, the measurements can beprocessed with respect to the forward and reverse power measurements(amplitude) which are coincident with the phase measurements todetermine which are valid and which were made in the presence of aninterferer, and ignore only those measurements, while using the validmeasurements in the algorithmic computations.

In another embodiment in which the detectors are complete receivers, theforward and reverse demodulated data can be compared to detectinterference. For example, complete receivers as detectors in both theforward and received sampled signal paths (such as shown in FIG. 8) canbe utilized. These receivers can be tuned specifically to the frequencyof the transmitted signal and can thus ignore any interfering signalsnot on the same frequency or channel. This aspect will eliminatevirtually all possible interfering signals in a normal implementation.Also, in this example, the forward and reverse samples should have thesame modulation as the desired transmitted signal. If an interferer ispresent, the receiver may either have the selectivity to ignore theinterferer or the received signal may be disrupted and the demodulateddata would not match the desired transmitted data. In this latter case,the measurements of forward and reverse power can then be ignored asbeing invalid.

In one embodiment, multiple fast samples can be taken to detectpeaks/nulls that are indicative of interference. For instance, aninterfering signal mixing with the desired signals can create a “beatnote” in the amplitude. By taking amplitude measurements at very highspeeds, method 900 can detect the effective amplitude modulation. If theamplitude modulation exceeds the desired transmitted signal modulationthen the measurement can be designated as invalid.

In another embodiment, phase measurements can be analyzed and comparedto a threshold for erratic shift (for example applying a 50 ohmexclusion) Phase measurements between non-coherent signals (such asbetween an interferer and a desired signal) can give random results.Phase measurements between coherent signals (such as the forward andreflected signals) which are close to 50 ohms can also give randomresults. Phase measurements between coherent signals that are not veryclose to 50 ohms are relatively stable. If phase signals are erratic(such as change by more than a certain amount between two readings or astandard deviation greater than a certain value or some other method ofdetecting erratic measurements) then the reflected signal may be aninterferer. In one embodiment, the algorithm can be turned off only ifboth erratic phase is present and the return loss is larger than acertain value (away from 50 ohms).

In another embodiment, sampling can be performed during transmission andwhen the transmitter is off. For instance, DTX can be used in WCDMA/CDMAto find times when the transmitter is off. In GSM or other Time Divisionsystems, intervals between transmit bursts can be used. A threshold canbe compared and applied to a reflected input. If the measured levelsduring transmission are too close to the levels when the transmitter isoff, then the measurement can be deemed invalid. In one embodiment,multiple measurements can be used to detect pulsed interferers.

In one embodiment, an AIMM engagement threshold and Reflection Loss (RL)targets based on detected reflected input (when not transmitting) can bevaried. When the transmitter is not active, a measurement of thereflected port can be taken. This measurement can be used to detect aninterferer and measure its amplitude. The amplitude of the interferercan be used to set a threshold for the reflected power below which themeasurement would be deemed invalid. The interferer level could also beused to adjust the RL target of the algorithm's figure of merit underinterferer conditions.

In another embodiment, measurements can be performed both before andafter known transmit power level changes and then changes can becompared to predicted change. For instance, the cellular handsetcontroller has knowledge of the power level at which it is transmittingand also the size of any intentional changes to the transmitted powerlevel. To test for the presence of an interferer, the tuning can be keptstatic and the detected powers/return loss can be measured. If thedetected change in power measurements are not within a preset toleranceof the known intentional change, the measurement can be determined to bedegraded by an interferer, and measurements can be deemed invalid.

In one embodiment, tuning can be prevented if the RL detected is greaterthan zero. For instance, if the measured RL is greater than zero (or apredetermined value to allow measurement uncertainty or othervariations), then the existence of an interferer has been determined.The predetermined value can further include design knowledge of thetuner and antenna load in a specific application.

If the measurements are determined to be valid then the tuning can beperformed as in step 910 to achieve the impedance matching. If on theother hand, the measurements are deemed invalid (such as through theexistence of an interferer) then the algorithm can ignore the lastinputs and retain the previous tuning state as in step 910. Thealgorithm can then continue normally and take the next scheduledmeasurements and again gauge the validity of those measurements. Thealgorithm can maintain the last known good tuning state until validmeasurements allow the algorithm to continue tuning the matching networkaccording to the figure of merit.

Method 900 can apply a number of thresholds in determining the validityof the measurements and detecting the existence of an interferer. Forexample, the cellular handset controller has knowledge of the powerlevel at which it is transmitting. The AIMM algorithm can be disabled ifthe known transmit power level is below a predetermined threshold.

Detected levels of interference can be used to set the AIMM on/offcontrol. For example, reflected power measurements that exceed certainthresholds can be invalidated. The thresholds can be dynamic and set asa function of the known transmitted power level, and also as a functionof the RL target for the particular channel/use case currently beingtuned. As another example, detected level of forward power can bemonitored. The cellular handset controller has knowledge of the powerlevel at which it is transmitting. If the forward power detected is innot within a set limit of the desired level, the measurements of bothforward and reflected power can be deemed invalid.

In one embodiment, with phase-based tuning algorithms (using impedancetargets), predicted RL improvements based on known techniques can becompared to actual measured RL improvements. With RL phase informationand a look-up table (LUT) (predetermined open-loop typical tuning statevalues) or calculations (using known/expected tuner LUT), antennaimpedance can be predicted, and correspondingly the tuning state inwhich to set the tuner can be determined in order to achieve the desiredmatch. After changing the tuning state, if the change in RL/impedance isnot within a predetermined threshold of the expected result, then it canbe determined that the measurement is being degraded by an interferer,and deemed invalid. The tuner can be restored to its last known good orvalid tuning state (such as a default state).

In another embodiment, the tuning range can be limited to increase tunerattenuation at known interferer frequencies.

In typical embodiments there may be additional limitations in thecircuitry such as noise thresholds caused by non-coherent signals fromwithin or without a cellular handset or other radio which could affectthe validity of detected signals used by an adaptive tuning network.While most of this specification describes the sources of theselimitations as interfering signals, this invention is not limited tojust the consideration of such signals. The exemplary embodiments can beutilized for tuning of a variable matching network in a communicationdevice based on all types of interference or undesired conditionsaffecting the communication device. The exemplary embodiments can applyanomaly detection to the tuning algorithm for determining a tuningstate.

In one embodiment, a low pass filter can be implemented that eliminatesinterferers outside of the filter bandwidth. Quadrature mixers can beutilized to avoid cancellation due to in-phase forward and reflectionsignals. The particular configuration of the components can vary. Forinstance, a low pass filter and a 90 degree phase shifter can beutilized, and can be incorporated into or otherwise implemented from,the transceiver components. In one embodiment, a VCO can be utilizedthat is running at twice the frequency and flip-flops can be used fordividing.

In exemplary embodiment 1000 and its corresponding frequency graph 1100,which are shown generally in FIGS. 10 and 11, low pass filters (LPFs)can be utilized to reduce or eliminate all interferers outside thefilter bandwidth. The return loss magnitude and/or phase can be obtainedby combining fp_I_flt, fp_Q_flt, rp_I_flt, rp_Q_flt in the analog ordigital domain. Quadrature mixers can be utilized to avoid cancellationdue to RF and LO being in-phase. One or more of the LPFs can be set atvalues low enough so that AM modulation may be removed.

In one embodiment, the forward signal can be utilized as the LO for theI and Q mixers on the detection IC of embodiment 1000. This eliminatesthe need for the transceiver IC to provide the LO signal. Anotheradvantage of this method is that the transmit modulation will be presenton the LO signal. The modulation envelope can then be eliminated by themixers. With the modulation eliminated, the baseband lowpass filter canbe wider, allowing for a faster measurement than if the LPF had to beset low enough to filter out the modulation. When using the forwardsignal for the LO, a BPF may be employed to improve performance byattenuating any interferers that may have coupled on to the forwardsignal.

This exemplary embodiment contemplates use of the same LO as thetransmitter or use of a different LO, such as a stand-alone LO (e.g.,generated by an IC detector) which can be phase-locked with thetransmitter.

In exemplary embodiment 1200 shown generally in FIG. 12, low passfilter(s) (LPFs) can be utilized in combination with power and phasedetectors and other control logic for tuning and filtering outinterference. In one embodiment, ph1 can be sweeped to maximize node Gwhile ph2 is sweeped to maximize node G2. Other components can beutilized with embodiment 1200, such as an amplitude detector and/or aphase modulator. The RL and phase can be computed.

In another exemplary embodiment 1300 shown generally in FIG. 13, thesweeping and computation described with respect to FIG. 12 can beperformed. The LO can be taken from the transmitter, prior to poweramplification (PA). For instance, the LO can be obtained from the inputto the PA, which may be more accessible to the tuning components. The PAcan provide isolation from any interferer and provide a clean LO. Thelimiter can be utilized to strip away the envelope of the amplitudemodulation.

In another exemplary embodiment 1400 shown generally in FIG. 14, thesweeping and computation described with respect to FIG. 12 can beperformed. The LO can be taken from the forward power (FP). The FP canbe filtered to reduce the effect of the interferer on the LO. In thisembodiment, the RF coupler and the bandpass filter can be integrated,such as made from the same ceramic structure.

In the embodiments of 1200-1400, the sensed DC voltage thru the ADC canbe used to control the ph1 and the ph2. When the ph1, ph2 is such thatthe DC voltages are maximized, then the two signals into the mixer aredeemed to be in-phase. Ph1 can be adjusted to increase or otherwise makeoptimum the forward power measurement. Ph2 can also be adjusted toincrease or otherwise make optimum the reflected power measurement. Thepower can be detected when phase difference between the two inputs ofthe mixer is zero degrees. These exemplary embodiments can ensure thatthe phase difference does not contribute to the power measurements. TheRL can be calculated from the power measurements, and the phasedifference is equal to ph2−ph1. The phase difference can be computedafter power measurements have been determined for stable phase errormeasurement. A limiter can remove amplitude modulation on a transmittedsignal (desired or undesired modulation). The limiter can act as afilter on forward power signal. Interfering signals may act to increasejitter on FP clock into mixer and can generate odd harmonics. A phasedelay can be utilized in measured RF signal path to ensure that the ph1and ph2 do not go negative. An amplifier can be utilized, but in oneembodiment the amplifier can be utilized for only the dynamic rangerequirements of the mixer. A baseband low pass filter can rejectinterferers outside of the filter bandwidth. The LPF can also be used tofilter out the AM on the modulated signal. If the AM remains, forwardand reflected signal can be sampled at the same time. Multiple samplescan also be utilized to avoid nulls.

In exemplary embodiment 1500 shown generally in FIG. 15, bandpass andlow pass filter(s) (BPF and LPF) can be utilized with a shared limiter.The shared limiter can be utilized to reduce phase error betweentransmit and reflected measurements. Various other components andconfigurations can also be utilized to reduce current drain and/orreduce die area. This embodiment allows obtaining data based on filteredforward power.

In exemplary embodiment 1600 shown generally in FIG. 16, bandpass andlow pass filter(s) (BPF and LPF) can be utilized with a shared delayclock. The shared delayed clock can be utilized to allow for phasedifference to be determined by ph2 only. While not shown, a bandpassfilter can be utilized, along with one or more other componentsdescribed in FIGS. 12-15. In one example, embodiment 1600 can utilize aphase-shifted LO from the forward power for the reverse power.

FIG. 17 illustrates an example of timing that can be utilized for one ormore of the tuning embodiments described herein, such as for a GSM/EDGEdevice. Forward and reverse power measurements can be made at the timeperiods indicated in time slots three and four. If the power detectedoutside of the transmission burst is above a threshold, then themeasurement made during a burst can be deemed invalid. In thisembodiment, frames are 4.615 ms and slots are 577 us, however other timeperiods may also be utilized.

FIG. 18 illustrates an example of timing that can be utilized for one ormore of the tuning embodiments described herein, such as for a WCDMAdevice. Forward and reverse power measurements can be made at the timeperiods indicated in FIG. 18. If the power detected outside of thetransmission burst is above a threshold, then the measurement madeduring the transmission can be deemed invalid.

A number of techniques can be utilized for validating return lossmeasurements. Measurements can be deemed invalid if: multiple fastmeasurements of the reflected port are taken and amplitude variationsare detected which exceed the known envelope modulation; multiple fastmeasurements of transmit minus reflected values show amplitudevariations (this method can cancel the transmit modulation and detectsan interfering beat note); and multiple fast measurements are takenduring transmission, excessive phase variation between measurements canbe indicative of an interferer, and if the range of measurements exceedsa set threshold. In one embodiment, when using a “one step” tuningmethod, which uses impedance measurement to tune to a known match, notseeing a RL after the adjustment within an expected threshold wouldinvalidate the tuning step, and the algorithm would then return to thelast known good tuning state.

Additional validity methods, such as through use of peak and averagedetectors. For example, forward and reverse measurements are done withboth Peak and Average detectors and compared. If the error exceeds theexpected (modulation) peak-to-average ratio by a set threshold,measurements are deemed invalid. Using Peak and Average detection on theforward minus reverse summed signal can cancel the transmittedmodulation and any difference should be due to interference, and thuscompared to a set threshold for invalidity.

In exemplary embodiment 1900 shown generally in FIG. 19, a Costas Loopcan be utilized where the forward power is relied upon to lock the localoscillator. The LPF in front of the LO can be set at a low enoughfrequency to strip off the angle modulation of the TX waveform. Inanother embodiment, a filter in the forward power path and/or in thereverse power path can be utilized. In another embodiment, where thelevel of the interferer is low enough, no filter may be needed.Embodiment 1600 can utilize an internal LO that is phase-locked to theforward power without the need for an external LO.

From the foregoing descriptions, it would be evident to an artisan withordinary skill in the art that the aforementioned embodiments can bemodified, reduced, or enhanced without departing from the scope andspirit of the claims described below. For example, the detection of aninterferer can be used to determine whether even to perform thealgorithm that determines the tunable state. For example, the detectionof an interferer can result in the device determining a tuning statebased on open-loop feedback rather than closed-loop feedback.Additionally, one or more of the steps described herein can be performedby a component of the transceiver. This can include incorporatingparticular components into the transceiver or utilizing already existingcomponents of the transceiver. Other suitable modifications can beapplied to the present disclosure. Accordingly, the reader is directedto the claims for a fuller understanding of the breadth and scope of thepresent disclosure.

FIG. 20 depicts an exemplary diagrammatic representation of a machine inthe form of a computer system 2000 within which a set of instructions,when executed, may cause the machine to perform any one or more of themethodologies discussed above. In some embodiments, the machine operatesas a standalone device. In some embodiments, the machine may beconnected (e.g., using a network) to other machines. In a networkeddeployment, the machine may operate in the capacity of a server or aclient user machine in server-client user network environment, or as apeer machine in a peer-to-peer (or distributed) network environment.

The machine may comprise a server computer, a client user computer, apersonal computer (PC), a tablet PC, a laptop computer, a desktopcomputer, a control system, a network router, switch or bridge, or anymachine capable of executing a set of instructions (sequential orotherwise) that specify actions to be taken by that machine. It will beunderstood that a device of the present disclosure includes broadly anyelectronic device that provides voice, video or data communication.Further, while a single machine is illustrated, the term “machine” shallalso be taken to include any collection of machines that individually orjointly execute a set (or multiple sets) of instructions to perform anyone or more of the methodologies discussed herein.

The computer system 2000 may include a processor 2002 (e.g., a centralprocessing unit (CPU), a graphics processing unit (GPU, or both), a mainmemory 2004 and a static memory 2006, which communicate with each othervia a bus 2008. The computer system 2000 may further include a videodisplay unit 2010 (e.g., a liquid crystal display (LCD), a flat panel, asolid state display, or a cathode ray tube (CRT)). The computer system2000 may include an input device 2012 (e.g., a keyboard), a cursorcontrol device 2014 (e.g., a mouse), a disk drive unit 2016, a signalgeneration device 2018 (e.g., a speaker or remote control) and a networkinterface device 2020.

The disk drive unit 2016 may include a machine-readable medium 2022 onwhich is stored one or more sets of instructions (e.g., software 2024)embodying any one or more of the methodologies or functions describedherein, including those methods illustrated above. The instructions 2024may also reside, completely or at least partially, within the mainmemory 2004, the static memory 2006, and/or within the processor 2002during execution thereof by the computer system 2000. The main memory2004 and the processor 2002 also may constitute machine-readable media.

Dedicated hardware implementations including, but not limited to,application specific integrated circuits, programmable logic arrays andother hardware devices can likewise be constructed to implement themethods described herein. Applications that may include the apparatusand systems of various embodiments broadly include a variety ofelectronic and computer systems. Some embodiments implement functions intwo or more specific interconnected hardware modules or devices withrelated control and data signals communicated between and through themodules, or as portions of an application-specific integrated circuit.Thus, the example system is applicable to software, firmware, andhardware implementations.

In accordance with various embodiments of the present disclosure, themethods described herein are intended for operation as software programsrunning on a computer processor. Furthermore, software implementationscan include, but not limited to, distributed processing orcomponent/object distributed processing, parallel processing, or virtualmachine processing can also be constructed to implement the methodsdescribed herein.

The present disclosure contemplates a machine readable medium containinginstructions 2024, or that which receives and executes instructions 2024from a propagated signal so that a device connected to a networkenvironment 2026 can send or receive voice, video or data, and tocommunicate over the network 2026 using the instructions 2024. Theinstructions 2024 may further be transmitted or received over a network2026 via the network interface device 2020.

While the machine-readable medium 2022 is shown in an example embodimentto be a single medium, the term “machine-readable medium” should betaken to include a single medium or multiple media (e.g., a centralizedor distributed database, and/or associated caches and servers) thatstore the one or more sets of instructions. The term “machine-readablemedium” shall also be taken to include any medium that is capable ofstoring or encoding a set of instructions for execution by the machineand that cause the machine to perform any one or more of themethodologies of the present disclosure.

The term “machine-readable medium” shall accordingly be taken toinclude, but not be limited to: solid-state memories such as a memorycard or other package that houses one or more read-only (non-volatile)memories, random access memories, or other re-writable (volatile)memories; magneto-optical or optical medium such as a disk or tape;and/or a digital file attachment to e-mail or other self-containedinformation archive or set of archives is considered a distributionmedium equivalent to a tangible storage medium. Accordingly, thedisclosure is considered to include any one or more of amachine-readable medium or a distribution medium, as listed herein andincluding art-recognized equivalents and successor media, in which thesoftware implementations herein are stored.

Although the present specification describes components and functionsimplemented in the embodiments with reference to particular standardsand protocols, the disclosure is not limited to such standards andprotocols. Each of the standards for Internet and other packet switchednetwork transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) representexamples of the state of the art. Such standards are periodicallysuperseded by faster or more efficient equivalents having essentiallythe same functions. Accordingly, replacement standards and protocolshaving the same functions are considered equivalents.

The illustrations of embodiments described herein are intended toprovide a general understanding of the structure of various embodiments,and they are not intended to serve as a complete description of all theelements and features of apparatus and systems that might make use ofthe structures described herein. Many other embodiments will be apparentto those of skill in the art upon reviewing the above description. Otherembodiments may be utilized and derived therefrom, such that structuraland logical substitutions and changes may be made without departing fromthe scope of this disclosure. Figures are also merely representationaland may not be drawn to scale. Certain proportions thereof may beexaggerated, while others may be minimized. Accordingly, thespecification and drawings are to be regarded in an illustrative ratherthan a restrictive sense.

Such embodiments of the inventive subject matter may be referred toherein, individually and/or collectively, by the term “invention” merelyfor convenience and without intending to voluntarily limit the scope ofthis application to any single invention or inventive concept if morethan one is in fact disclosed. Thus, although specific embodiments havebeen illustrated and described herein, it should be appreciated that anyarrangement calculated to achieve the same purpose may be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the above description.

The Abstract of the Disclosure is provided to allow the reader toquickly ascertain the nature of the technical disclosure. It issubmitted with the understanding that it will not be used to interpretor limit the scope or meaning of the claims. In addition, in theforegoing Detailed Description, it can be seen that various features aregrouped together in a single embodiment for the purpose of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed embodiments require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter lies in less than allfeatures of a single disclosed embodiment. Thus the following claims arehereby incorporated into the Detailed Description, with each claimstanding on its own as a separately claimed subject matter. It is alsocontemplated that features in one embodiment may be utilized withfeatures of another embodiment.

What is claimed is:
 1. A communication device, comprising: atransceiver; a tunable reactance circuit coupled to the transceiver; anda controller coupled with the tunable reactance circuit, wherein thecontroller, responsive to executing instructions, performs operationscomprising: determining a tuning state for the tunable reactance circuitbased on detected signal measurements; determining whether the detectedsignal measurements are valid or invalid; applying the tuning state tothe tunable reactance circuit responsive to a determination that thedetected signal measurements are valid; and applying one of a last knownvalid tuning state or a default tuning state to the tunable reactancecircuit responsive to a determination that the detected signalmeasurements are invalid.
 2. The communication device of claim 1,wherein the determining of the tuning state is based in part on amechanical use case of the communication device.
 3. The communicationdevice of claim 1, wherein the tunable reactance circuit comprises oneor more semiconductor varactors, one or more micro-electro-mechanicalsystems (MEMS) varactors, one or more semiconductor switched capacitors,one or more MEMS switched capacitors, or combinations thereof.
 4. Thecommunication device of claim 1, wherein the tunable reactance circuitcomprises a signal sampling network, and wherein a signal output of thesignal sampling network has a filter coupled thereto.
 5. Thecommunication device of claim 4, wherein the signal sampling networkcomprises a directional coupler.
 6. The communication device of claim 1,wherein the tunable reactance circuit comprises one or moreferroelectric capacitors.
 7. The communication device of claim 1,wherein the determining of whether the detected signal measurements arevalid or invalid is based on at least one of Voltage Standing Wave Ratiodata measured over a period of time, amplitude modulation, a reflectedinput measured during transmission and non-transmission, phasemeasurements outside of a standard deviation, a comparison of measuredand predicted transmission power level changes, or a comparison ofmeasured and predicted improvement in reflected loss between tuningstates.
 8. The communication device of claim 1, wherein the invalidityof the detected measurements is caused by another communication devicegenerating a signal that interferes with the communication device. 9.The communication device of claim 1, wherein the invalidity of thedetected measurements is caused by internal interference generated bythe communication device.
 10. A method comprising: determining, by aprocessor of a communication device, a tuning state for a tunablereactance circuit from among a plurality of tuning states based onwhether detected signal measurements are determined to be invalid andbased on information from at least one of an open-loop or closed-loopfeedback configuration of the tunable reactance circuit, wherein theprocessor is coupled with the tunable reactance circuit, wherein thetunable reactance circuit is coupled to at least one of a transmitterportion or a receiver portion of the communication device; adjusting thetunable reactance circuit utilizing the tuning state responsive to adetermination that the detected signal measurements are valid; andadjusting the tunable reactance circuit utilizing a previouslydetermined tuning state or a default tuning state responsive to adetermination that the detected signal measurements are invalid.
 11. Themethod of claim 10, wherein the open-loop feedback configuration isbased on a mechanical use case of the communication device
 12. Themethod of claim 10, further comprising determining a validity of thedetected signal measurements based on a comparison of measured andpredicted improvement in reflected loss.
 13. The method of claim 10,further comprising determining a validity of the detected signalmeasurements based on Voltage Standing Wave Ratio data measured over aperiod of time.
 14. The method of claim 10, further comprisingdetermining a validity of the detected signal measurements based onamplitude modulation.
 15. The method of claim 10, further comprisingdetermining a validity of the detected signal measurements based on areflected input level measured during transmission and non-transmission.16. The method of claim 10, further comprising determining a validity ofthe detected signal measurements based on phase measurements outside ofa predetermined deviation.
 17. The method of claim 10, furthercomprising determining a validity of the detected signal measurementsbased on a comparison of measured and predicted transmission power levelchanges.
 18. The method of claim 10, wherein the tunable reactancecircuit comprises at least one of one or more voltage tunablecapacitors, one or more semiconductor varactors, one or moremicro-electro-mechanical systems (MEMS) varactors, one or moresemiconductor switched capacitors, one or more MEMS switched capacitors,and one or more ferroelectric capacitors.
 19. A communication device,comprising: a transceiver; a tunable reactance circuit coupled to thetransceiver; and a controller coupled with the tunable reactancecircuit, wherein the controller, responsive to executing instructions,performs operations comprising: determining a tuning state for thetunable reactance circuit based on detected signal measurements andbased on a use case for the communication device; determining whetherthe detected signal measurements are valid or invalid; applying thetuning state to the tunable reactance circuit responsive to adetermination that the detected signal measurements are valid; andapplying a last known valid tuning state to the tunable reactancecircuit responsive to a determination that the detected signalmeasurements are invalid.
 20. The communication device of claim 19,wherein the determining of whether the detected signal measurements arevalid or invalid is based on at least one of Voltage Standing Wave Ratiodata measured over a period of time, amplitude modulation, a reflectedinput measured during transmission and non-transmission, phasemeasurements outside of a standard deviation, a comparison of measuredand predicted transmission power level changes, or a comparison ofmeasured and predicted improvement in reflected loss between tuningstates.